Featured Research

from universities, journals, and other organizations

Perception and preference may have genetic link to obesity

Date:

March 5, 2012

Source:

Rutgers University

Summary:

New discoveries suggest that fats are perceived on the tongue as a "taste" sensation by binding to specialized receptors on taste buds. More specifically, fats are broken down in the mouth to fatty acids, and it's the fatty acids that bind to these receptors.

Share This

About five years ago, animal studies first revealed the presence of entirely novel types of oral fat sensors or receptors on the tongue. Prior to this time, it was believed that fats were perceived only by flavor and texture cues. With this new information, "everything that we thought we knew about fat perception got turned on its head," said Beverly Tepper, a professor in the Department of Food Science at Rutgers School of Environmental and Biological Sciences.

Related Articles

Tepper has been studying consumer preferences for high-fat versus low-fat foods, and has been intrigued by the questions: "Why are some people more sensitive and others less sensitive to fat?" "Is this a personal trait?" "And do genes contribute to these differences?"

Those new discoveries suggest that fats are perceived on the tongue as a "taste" sensation by binding to specialized receptors on taste buds. More specifically, Tepper explained, "fats are broken down in the mouth to fatty acids, and it's the fatty acids that bind to these receptors."

One oral fat receptor that has attracted a great deal of recent attention is CD36, a carrier protein that helps fatty acids traverse cell membranes in many tissues of the body. This is necessary for fats to participate in many different metabolic functions. Recent studies show that CD36 is also located on the surface of taste buds and may send signals to the brain about the presence of fat in the mouth.

But how is CD36 related to consumer fat preferences and the possible genetic differences that Tepper and colleagues are so keen on understanding?

The answer lies in a new study published in the journal Obesity by Tepper, in conjunction with her former student Kathleen Keller, who received her Ph.D. in 2002 from Rutgers' graduate program in nutritional sciences. Keller, now an assistant professor of nutritional sciences at The Pennsylvania State University and lead author on the article, studied an overweight population of African-American adults and found those who had a specific change or variation in the CD36 gene perceived the creaminess and fattiness of salad dressings quite well, but they were less able to differentiate the high-fat from the low-fat versions.

Despite this insensitivity, these same individuals reported by questionnaire that they liked added fats such as salad dressings, spreads, butter and margarine more than those who did not have this variation in their CD36 gene. "This is the first time that a gene involved in fat taste has been linked to fat preference in humans," said Tepper.

A Genetic Marker for Fat Texture

This latest finding came out of years of research on PROP-tasting, a different genetic trait that seems to be an index of general food preferences, including liking of fat. PROP (short for propylthiouracil) is a bitter-tasting compound that is strong-tasting to some people and tasteless to others. The ability to taste PROP is controlled by a gene called TAS2R38. People who are taste-blind to PROP are called "non-tasters" and those who perceive PROP to be strongly bitter are called "super-tasters." Those in the middle of the pack, not surprisingly, are called "medium tasters."

"Several things became very clear from our studies and those from other labs," says Tepper. "Non-tasters were insensitive to a wide range of oral sensations such as bitterness, sweetness, chili pepper heat and the texture of fats, and they avidly consumed foods with these characteristics." At the other end of the spectrum were "super-tasters, who disliked strong tasting foods because they were too intense for them."

One area Tepper began focusing on was the perception and preference of fat since this has obvious implications for obesity development. In a series of studies, she asked participants to use their own words to describe dairy products that varied in fat content such as ice cream, sour cream, whole milk and skim milk. Super-tasters used a rich and varied vocabulary to describe these foods, whereas non-tasters used very few, simple words.

However, said Tepper, "even though the non-tasters had difficulty describing the foods, they knew what they liked, and they preferred the higher-fat products."

Until recently, it was unclear why a genetic trait that controls the ability to taste bitterness plays a role in fat perception. Why should these two behaviors be related at all?

According to Tepper, "the key linking these two factors together is differences in tongue anatomy." Super-tasters have more taste buds and more nerve fibers that carry signals to the brain about oral texture; non-tasters have fewer taste buds and nerve fibers. Since the perception of fat is due mostly to its texture -- flavor being the second component -- differences in the ability to sense the texture of fats seem to distinguish non-tasters from super-tasters.

Designer Fats and Personalized Diets

The ability to taste fatty acids provides important signals about the type of fat being consumed and the implications of this could be far reaching, suggested Tepper. "We could use this information to design more healthful fats that also give foods the high sensory appeal that consumers want."

"Using these two genetic markers, CD36 and PROP, we could identify those who are insensitive to oral fat and who may be more susceptible to high-fat diets and obesity," said Tepper. "We could devise more personalized diet strategies to address this specific dietary issue," she added.

"CD36 is only the beginning," added Tepper. "There is at least one additional fatty acid receptor that is known to exist in humans, and probably others that have yet to be identified."

More From ScienceDaily

More Health & Medicine News

Featured Research

Mar. 3, 2015 — New assays can detect malaria parasites in human blood at very low levels and might be helpful in the campaign to eradicate malaria, reports a new study. An international team led by Ingrid Felger, ... full story

Mar. 3, 2015 — Adults over the age of 30 only catch flu about twice a decade, a new study suggests. So, while it may feel like more, flu-like illness can be caused by many pathogens, making it difficult to assess ... full story

Mar. 3, 2015 — No significant change in home habits of smokers have been observed in the aftermath of a ban on smoking in public spaces, researchers report. Greater inspiration to kick the habit likely comes from ... full story

Mar. 3, 2015 — Heart function has been associated with the development of dementia and Alzheimer's disease through a new study. Participants with decreased heart function, measured by cardiac index, were two to ... full story

Mar. 3, 2015 — Children of recently separated or divorced families are likelier to drink sugar-sweetened beverages than children in families where the parents are married, putting them at higher risk for obesity ... full story

Mar. 3, 2015 — Gastric bypass and similar stomach-shrinking surgeries are a popular option for obese patients looking to lose weight or treat type 2 diabetes. While the surgeries have been linked to a decreased ... full story

Mar. 3, 2015 — Most people consume more salt than they need and therefore have a higher risk of heart disease and stroke, which are the two leading causes of death worldwide. But a new study reveals that dietary ... full story

Mar. 3, 2015 — Twice as many children born to mothers who took antibiotics during pregnancy were diagnosed with asthma by age 3 than children born to mothers who didn’t take prenatal antibiotics, a new study has ... full story

Mar. 3, 2015 — Although sedatives are often administered before surgery, a randomized trial finds that among patients undergoing elective surgery under general anesthesia, receiving the sedative lorazepam before ... full story

Featured Videos

Mom Triumphs Over Tragedy, Helps Other Families

AP (Mar. 3, 2015) — After her son, Dax, died from a rare form of leukemia, Julie Locke decided to give back to the doctors at St. Jude Children&apos;s Research Hospital who tried to save his life. She raised $1.6M to help other patients and their families. (March 3)
Video provided by AP

Looted and Leaking, South Sudan's Oil Wells Pose Health Risk

AFP (Mar. 3, 2015) — Thick black puddles and a looted, leaking ruin are all that remain of the Thar Jath oil treatment facility, once a crucial part of South Sudan&apos;s mainstay industry. Duration: 01:13
Video provided by AFP

Woman Convicted of Poisoning Son

AP (Mar. 3, 2015) — A woman who blogged for years about her son&apos;s constant health woes was convicted Monday of poisoning him to death by force-feeding heavy concentrations of sodium through his stomach tube. (March 3)
Video provided by AP

Sep. 30, 2014 — Dietary polyunsaturated fatty acids may reduce the risk of coronary heart disease, a recent study has found. The sources of polyunsaturated fatty acids include fish, vegetable oils, and nuts. The ... full story

June 3, 2014 — Oral taste cells contain receptors for glucocorticoid “stress hormones,” new research shows. The findings suggest glucocorticoids may act directly on taste cells to affect how they respond to ... full story

Mar. 22, 2012 — While high-fat foods are thought to be of universal appeal, there is actually a lot of variation in the extent to which people like and consume fat. A new study reported that two specific genes ... full story

Mar. 10, 2010 — A newly discovered ability for people to taste fat could hold the key to reducing obesity, researchers believe. They also found that people with a high sensitivity to the taste of fat tended to eat ... full story

ScienceDaily features breaking news and videos about the latest discoveries in health, technology, the environment, and more -- from major news services and leading universities, scientific journals, and research organizations.